Pregnant women who limit sedentary time to about eight hours daily and engage in at least seven hours of light physical activity may reduce their risk of developing hypertensive disorders by nearly 30%, according to preliminary research presented at the American Heart Association's EPI|Lifestyle Scientific Sessions 2026. The study of 470 women across three U.S. cities found that sedentary behaviors and light physical activity were the strongest predictors of hypertensive disorder risk across all pregnancy trimesters.
The research highlights the importance of daily movement patterns rather than just traditional exercise. Women with the lowest-risk daily pattern—approximately six hours of sitting, nearly eight hours of light physical activity, four minutes of higher-intensity activity, and roughly ten hours of rest—had an 8% chance of developing hypertensive disorders compared to 16.9% among those with typical daily patterns. When compared to the least healthy movement patterns measured, the optimal activity combination reduced risk by nearly 80%.
"Our study suggests that in the real world, where daily routines vary widely, it may actually be the balance of sitting time and light intensity movement across the entire day that matters most," said lead study author Kara Whitaker, Ph.D., M.P.H., FAHA, an associate professor at the University of Iowa. "This doesn't mean exercise isn't beneficial—rather, that when it comes to hypertensive disorders of pregnancy, everyday movement and limiting long periods of sitting may play a bigger role than we previously understood."
The findings have significant implications for maternal and fetal health, as high blood pressure develops in up to 5%-10% of all pregnancies and is the leading cause of fetal and maternal disease and death. According to the American Heart Association, high blood pressure during pregnancy and other adverse pregnancy conditions are associated with an increased risk of future cardiovascular disease. The study results align with the American Heart Association's Life Essential 8 for Pregnancy recommendations, which encourage women to find ways to move throughout the day.
Natalie A. Bello, M.D., M.P.H., an American Heart Association volunteer expert not involved with the study, noted that "both sedentary behavior and hypertension in pregnancy are increasingly common, and in non-pregnant individuals we know that physical activity is associated with reductions in blood pressure. The researchers extend this to the pregnant population where nearly 20% of participants developed a hypertensive disorder of pregnancy."
The study measured activity using wearable monitors that tracked time spent lying down, sitting, standing, and walking during each trimester. Researchers found risk increased for women who sat more than ten hours daily or had less than five hours of light activity. "These findings have the potential to shift how we think about physical activity and sleep during pregnancy," Whitaker said. "Right now, there are no clear, quantitative guidelines for how much sitting or light intensity movement is healthiest during pregnancy, and our results provide early evidence that could help shape those recommendations in the future."
Study limitations include that participants were mostly white with higher education and income levels, so results may not reflect other population groups. Researchers also couldn't analyze preeclampsia and gestational hypertension separately due to relatively small case numbers. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal, as abstracts presented at American Heart Association scientific meetings are not peer-reviewed.
